A light-sensitive material which comprises a support and a light-sensitive layer containing silver halide, a reducing agent and a polymerizable compound can be used in an image forming method in which a latent image of silver halide is formed, and then the polymerizable compound is polymerized to form the corresponding image.
Examples of said image forming methods are described in Japanese Patent Publication Nos. 45(1970)-11149 (corresponding to U.S. Pat. No. 3,697,275), 47(1972) -20741 (corresponding to U.S. Pat. No. 3,687,667) and 49(1974)-10697, and Japanese Patent Provisional Publication Nos. 57(1982)-138632, 57(1982)-142638, 57(1982)-176033, 57(1982)-211146 (corresponding to U.S. Pat. No. 4,557,997), 58(1983)-107529 (corresponding to U.S. Pat. No. 4,560,637), 58(1983)-121031 (corresponding to U.S. Pat. No. 4,547,450) and 58(1983)-169143. In these image forming methods, when the exposed silver halide is developed using a developing solution, the polymerizable compound is induced to polymerize in the presence of a reducing agent (which is oxidized) to form a polymer image. Thus, these methods need a wet development process employing a developing solution. Therefore the process takes a relatively long time for the operation.
An improved image forming method employing a dry process is described in Japanese Patent Provisional Publications Nos. 61(1986)-69062 and 61(1986)-73145 (the contents of both publications are described in U.S. Pat. No. 4,629,676 and European Patent Provisional Publication No. 0174634A2). In this image forming method, a recording material (i.e., light-sensitive material) comprising a light-sensitive layer containing a light-sensitive silver salt (i.e., silver halide), a reducing agent, a cross-linkable compound (i.e., polymerizable compound) and a binder provided on a support is imagewise exposed to form a latent image, and then the material is heated to polymerize within the area where the latent image of the silver halide has been formed.
The above-mentioned image forming methods are based on the principle in which the polymerizable compound is polymerized within the area where a latent image of the silver halide has been formed.
Japanese Patent Provisional Publication No. 61(1986) -260241 describes another image forming method in which the polymerizable compound within the area where a latent image of the silver halide has not been formed is polymerized. In this method, when the material is heated, the reducing agent functions as polymerization inhibitor within the area where a latent image of the silver halide has been formed, and the polymerizable compound within the other area is polymerized.
The polymerization reaction in the image forming method smoothly proceeds under alkaline conditions. Therefore, a base or base precursor is preferably contained in the light-sensitive layer. Examples of the base and base precursor are described in Japanese Patent Provisional Publications Nos. 61(1986)-69062, 61(1986)-73145 and 61(1986)-260241. However, where the light-sensitive layer contains a base or a base precursor in the light-sensitive layer (particularly when the base is contained), the sensitivity of the light-sensitive material tends to decrease or the material tends to be fogged in the course of the storage.
In order to eliminate the above-mentioned problem, the base or base precursor may be separated from the other components of the light-sensitive layer, and the base or base precursor may be brought into contact with the others in a development process. An example of the light-sensitive material employing a separating means is described in Japanese Patent Provisional Publication No. 62(1987)-209523. In the light-sensitive material, the components of the light-sensitive layer, such as silver halide, a reducing agent and a polymerizable compound is contained in microcapsules to form light-sensitive microcapsules, and the base or base precursor is arranged outside of the light-sensitive microcapsules. The light-sensitive material employing the microcapsules has other advantages in that the sharpness of an image is improved and a clear image can be obtained.